As long as she has not been prolapsed too long, you can save her. Get her cleaned up push all her insides back inside. Use the prep H on her vent and inside too to reduce the swelling. Keep her by herself. The others will pick her to death. You will also need to get her to stop laying so she can heal. So keep her in a semi darkened area, only 8 hours of dim light a day. The rest darkness. This should stop the laying. Keep her like this until she is completely healed.

You will probably need to reintroduce her to the flock slowly from a cage or enclosure within the coop and run. The flock will no doubt have forgotten her. Leave her caged for about 3 weeks and then you can mix her back in. Watch for any aggression and always intervene if it turns bloody. Put out more food and water stations for a while so you know she is eating.